Integrated circuits, such as memory devices, are continually being reduced in size. As such, the size of the features that form the integrated circuits, such as conductive lines, is also being decreased. For example, the internal lines, e.g., control signal lines, address signal lines, and DQ signal lines, within a memory device, such as dynamic random access memory (DRAM), flash memory, static random access memory (SRAM), ferroelectric (FE) memory, etc., are becoming smaller. In some applications, these internal lines may be connected to conductive pads, e.g., sometimes called “landing” pads, of the memory device, such as conductive pads mounted on a memory chip (e.g., memory die). For example, the conductive pads may be connected to pins or other conductive pads on a printed circuit board that forms a portion of a memory package.
Pitch is a quantity commonly used when addressing the spacing between neighboring features, such as adjacent conductive lines, in an integrated circuit. For example, pitch may be defined as the center-to-center distance between two adjacent lines. Lines are typically defined by spaces between adjacent lines, where the spaces may be filled by a material, such as a dielectric. As a result, pitch can be viewed as the sum of the width of a line and of the width of the space on one side of the line separating that line from an adjacent line. However, due to factors such as optics and light or radiation wavelength, photolithography techniques each have a minimum pitch below which a particular photolithographic technique cannot reliably form lines. Thus, the minimum pitch of a photolithographic technique is an obstacle to continued line size reduction.
“Pitch multiplication,” such as “pitch doubling,” is commonly used for extending the capabilities of photolithographic techniques beyond their minimum pitch. The pitch is actually reduced by a certain factor during “pitch multiplication.” For example, the pitch is halved during “pitch doubling.”
Conductive pads can be larger than the conductive lines and the pitch, e.g., especially when using pitch multiplication, making it difficult to couple a conductive pad to a line without contacting an adjacent line with a single conductive pad or without conductive pads coupled to adjacent lines contacting each other, thereby shorting the adjacent lines together. Therefore, an additional mask is sometimes used during the pitch-multiplication process to redistribute portions of the lines to increase the spacing where the conductive pads are to be coupled.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative pitch multiplication techniques.